Holter Monitoring Research Articles

Comparing the effects of three local anaesthetic agents on cardiac conduction system - A randomised study.

This study aimed to compare the effects of three local anaesthetic (LA) agents, namely bupivacaine, levobupivacaine, and ropivacaine, on the cardiac conduction system as assessed by corrected QT (QTc) and P wave dispersion (PWD) intervals in lower limb orthopaedic surgeries and to find the most suitable LA agent that can be used for a long duration. The study included 75 patients with American Society of Anesthesiologists physical status I and II of either gender in the age group of 18-65 years undergoing elective lower limb orthopaedic surgeries under epidural anaesthesia. These were allocated to groups B (bupivacaine), L (levobupivacaine), and R (ropivacaine). We observed blood pressure, heart rate, respiratory rate, PWD, and QTc intervals from baseline value through Holter monitoring, pain assessment by visual analogue scale, and demand and total volume of LA consumed by patient-controlled analgesia devices. The repeated measures of ANOVA were carried out to find the effect of time and time-to-group interaction among the groups across the periods. On intergroup comparison of QTc and PWD, no significant difference among groups was observed, but on intragroup analysis, a statistically significant increase in QTc and PWD from baseline was observed for each of groups B, L, and R at all time intervals. However, the mean increase in QTc and PWD recorded for Group B was higher than in groups L and R. Bupivacaine has the maximal tendency to prolong QTc and PWD. All three agents showed comparable haemodynamic effects and time to onset of sensory and motor blockade.

Tyrosine hydroxylase-positive neurons in the rostral ventrolateral medulla mediate sympathetic activation in sepsis

AimSepsis results in high mortality and is associated with organ dysfunction caused by infection. The present study aimed to elucidate whether early-stage sympathetic activation is associated with the prognosis of sepsis and its possible mechanisms. MethodsPatients with sepsis and healthy controls were included. Sepsis in rats was induced by lipopolysaccharide. Dexmedetomidine, a α2-adrenergic receptor agonist, was used in patients and rats with sepsis to evaluate the role of the sympathetic nervous system in sepsis. Holter monitoring was used to detect heart rate variability, while plasma samples were obtained to measure levels of norepinephrine and inflammatory markers. Mean arterial pressure, heart rate, and renal sympathetic nerve activity were recorded. Immunofluorescence was used to detect the activation of neurons in the rostral ventrolateral medulla (RVLM). ResultsIn patients with sepsis, plasma levels of norepinephrine and interleukin-1β were higher compared with those in controls and positively correlated with acute physiology and chronic health evaluation (APACHEII). SDNN and SDANN were significantly reduced as well as negatively correlated with APACHEII. Meanwhile, rats with sepsis showed increased of sympathetic outflow and plasma levels of norepinephrine, with increased c-fos levels in the RVLM. Treatment with dexmedetomidine could improve prognosis. Lesion of tyrosine hydroxylase-positive neurons in the RVLM attenuated sympathetic activation and target organs damage in septic rats as well as improved survival. ConclusionThe results suggest that tyrosine hydroxylase-positive neurons in the RVLM might contribute to the prognosis of sepsis via activation of the sympathetic nervous system, while dexmedetomidine could ameliorate sepsis via inhibiting sympathetic activation.

Analysis of Thyroid Disorders in the Occurrence of Paroxysmal Atrial Fibrillation

Thyroid disorders can directly affect the cardiovascular system, especially atrial fibrillation arrhythmia. Atrial fibrillation can be triggered by hormonal changes in the human body system. This can be dangerous and can increase the risk of stroke in sufferers. For this reason, researchers conducted this study to be able to analyze the risk of atrial fibrillation due to thyroid disorders. This study used a retrospective analytical design, with a chi square test to determine the risk of increased atrial fibrillation due to thyroid disorders. This study was conducted at Budhi Asih Hospital with Holter monitoring patient samples. The results of this study showed that in patients with thyroid disorders, the results of Holter monitoring showed paroxysmal atrial fibrillation as much as 9.9%, with a p-value: 0.000; OR: 39.346. The conclusion is that there are significant results between thyroid disorders and the incidence of paroxysmal atrial fibrillation

The ECG of a 6-year-old girl

A 12-channel ECG and the ECG patterb from Holter monitoring of a 6-year-girl are presented.

Effects of Ventricular Extrasystoles on Right Ventricle Functions (a Speckle Tracking Study). VES and RV Strain Imaging.

The adverse effects of ventricular extrasystoles (VES) on the heart, such as induced dyssynchrony, irregular heart rate, and atrioventricular dissociation, have been demonstrated. The aim of this study was to investigate the effects of VES on the right ventricle (RV) using strain imaging. Fifty patients with 5000 or more VES detected during 24hr Holterrhythm monitoring between April 2022 and September 2022 in the cardiology outpatient clinic were included in this study.A volunteer control group of 50 individuals matching the patients' age and demographic characteristics was selected. Right heart function parameters were compared echocardiographically between the two groups. In the VES group, both RV free wall strain (22.03±3.67, 29.52±3.01; p<0.001) and RV four-chamber strain (19.37±2.95, 22.34±2.11; p<0.001) were lower compared to the control groupIn the univariate regression analysis for decreased RV four-chamber strain, the presence of VES (p<0.001) was identified as a predictor, whereaas in the multivariate regression analysis, it was not considered to be an independent predictor. When evaluating the characteristics of the VES patients, the number of VES detected during Holter monitoring and delta QRS were observed as negative predictors of RV strain. This study demonstrated the adverse effects of VES on the right ventricle, as it is on the left ventricle.Therefore, regular monitoring of RV function with echocardiography is important in the follow-up of patients with VES.

The impact of regular physical training on the function of the autonomic nervous system in patients with inappropriate sinus tachycardia

Introduction: Sympathetic overactivity plays a crucial role in the pathogenesis of inappropriate sinus tachycardia (IST). It has been shown that regular physical activity positively affects the balance between the sympathetic and parasympathetic nervous systems, which may benefit patients with IST.Objective: This study aimed to assess the impact of regular physical training on the autonomic nervous system (ANS) function in patients with IST, focusing on heart rate variability (HRV) as an indicator of autonomic balance.Methods:The study included 32 female patients diagnosed with IST, with 16 in the study group (Group A) and 16 in the control group (Group B). The women in Group A participated in a structured physical training program lasting 12 weeks. HRV was analyzed based on 24-hour Holter monitoring recordings before and after the intervention. The statistical data obtained were presented as graphs illustrating changes in selected HRV parameters in response to physical training.Results:The study results indicate a significant improvement in heart rate variability (HRV) after 12 weeks of regular physical training in the study group. Notably, there was an increase in parameters associated with parasympathetic activity, such as the HF (High Frequency) index. Additionally, the SDNN index, which measures overall heart rate variability, also improved. These observations suggest that physical training contributed to an improvement in autonomic balance. The graphs in the study clearly depict changes in individual HRV parameters, confirming the positive impact of physical activity on the function of the autonomic nervous system in patients with IST.

Concentration-QTc analysis of soticlestat in healthy adults: An alternative to a thorough QT study.

This study aimed to examine the cardiac and overall safety and pharmacokinetic (PK) profiles of soticlestat (TAK-935), an oral, first-in-class selective cholesterol 24-hydroxylase inhibitor. Data came from a randomised, phase 1 study of soticlestat in 33 healthy Japanese adults (NCT04461483); 24 adults in Part 1 (single-dose soticlestat 200-1200 mg or placebo) and 9 in Part 2 (soticlestat 100-300 mg twice daily or placebo for 21 days). PK sample collection was paired with 12-lead electrocardiogram data from continuous Holter recordings. The concentration-QTc relationship was analysed using a linear mixed-effects model. QTc prolongation safety margins were determined for two scenarios of calculated high clinical exposures: scenario 1 (NCT05064449) involved coadministration of single-dose soticlestat 300 mg with itraconazole or mefenamic acid and scenario 2 (NCT05098054) involved single-dose soticlestat 300 mg administration in participants with mild/moderate hepatic impairment (implementing a 3-fold dose reduction for moderate severity). Based on concentration-QTc analysis, placebo-corrected change-from-baseline QT values (90% confidence intervals), corrected for heart rate (Fridericia's method), were 0.94 ms (-2.35, 4.23) for soticlestat and 0.63 ms (-3.15, 4.41) for its N-oxide metabolite plasma concentrations at therapeutic doses (soticlestat 300 mg twice daily); safety margins were >2-fold for scenarios of calculated high clinical exposures. No (Part 1) and five (83.3%; Part 2) participants experienced treatment-emergent adverse events (all mild). There was no evidence for QT prolongation with soticlestat at therapeutic doses or in two scenarios of high clinical exposures, which resulted in regulatory agencies waiving requirements of a thorough QT study. Safety/PK findings aligned with previous soticlestat clinical studies.

Adiposity and cardiac autonomic function in children with a family history of obesity.

Data on associations between adiposity and heart rate variability (HRV) in prepubertal children are limited. We examined the associations between adiposity indices and HRV, independent of lifestyle behaviors, comparing multiple indicators of adiposity, and explored differences between boys and girls. Data stem from 469 participants of the QUALITY cohort (630 children aged 8-10 years with a parental history of obesity). Adiposity indices included waist-to-height ratio, body mass index (BMI) percentiles and categories (overweight, obesity), dual-energy x-ray absorptiometry (DEXA) defined fat mass percentage and android/gynoid ratio. HRV indices in the frequency and the spectral domain were derived from a daytime 3-h Holter recording. Multivariable linear regression models were adjusted for age, sex, Tanner stage, physical activity, screen time, and fitness. Interactions between sex and adiposity were tested. Greater adiposity was associated with decreased parasympathetic modulation and increased sympathetic dominance. Waist-to-height ratio was associated with lower parasympathetic activity: root mean square of the successive differences (RMSSD) [B = -23.32, 95% confidence interval (CI) -42.42, -4.22], pNN50 (B = -16.93, 95% CI - 28.58, - 5.27), LF/HF ratio (B = 1.83, 95% CI 0.97-2.70). Patterns of association were similar for android/gynoid ratio. Overweight was not associated with altered HRV. Obesity was negatively associated with RMSSD and pNN50 and positively with LF/HF ratio. Greater fat mass percentage was associated with lower RMSSD, pNN50, and HF, and increased LF/HF ratio. There were no differences between boys and girls. Specific markers of adiposity relate to altered HRV in childhood, with waist-to-height ratio being potentially a more relevant marker of HRV than BMI and more pragmatic than percent body fat. NCT03356262, 11 November 2017.

The role of vector-borne pathogens and cardiac Striatin genotype on survival in boxer dogs with arrhythmogenic right ventricular cardiomyopathy

Introduction/ObjectivesRisk factors for severe disease in boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC) are not well understood. This study's objective was to determine whether Striatin genotype or canine vector-borne pathogen (CVBP) exposure/infection in boxer dogs with ARVC was associated with disease severity or survival. AnimalsSixty-four client-owned, adult boxer dogs with ARVC were included in the study. Materials and MethodsThis was a prospective descriptive study. Disease severity was determined by echocardiography and Holter monitoring. Potential risk factors included CVBP exposure/infection (Anaplasma spp., Babesia spp., Bartonella spp., Borrelia burgdorferi, Dirofilaria immitis, Ehrlichia spp., and Rickettsia spp.) and Striatin genotype. ResultsThe median survival time after enrollment was 270 days (95% confidence interval [CI]: 226–798 days), and the median age at the time of death or censoring was 11 years (95% CI: 10.3–11.7 years). Striatin mutation genotype results included 31 homozygous-negative, 26 heterozygous-positive, and seven homozygous-positive boxer dogs. Ten boxer dogs had exposure to Bartonella spp., four to Rickettsia, two to Ehrlichia spp., and one to Anaplasma spp. Striatin homozygous–positive boxer dogs had a shorter median survival time (93 days vs. 373 days for heterozygous [P=0.010] and 214 days for homozygous negative [P=0.036]). Exposure/infection to CVBP was not associated with median survival time or age at the time of death. DiscussionStriatin homozygous positive boxer dogs with ARVC had shorter survival times and were younger at the time of death. Exposure or infection with CVBP did not appear to influence survival time. Study LimitationsSelection bias for more severe disease limited the ability to assess the relationship between CVBP infection/exposure and disease severity, and overall small sample size limited statistical power. Extracardiac disease and treatment protocols were not controlled. ConclusionsStriatin genotype screening can be considered for prognostic information. Exposure/infection to CVBP appears unlikely to influence survival time for boxer dogs with ARVC.

The Prevalence of Arrhythmias, Including Premature Supraventricular and Ventricular Beats and Other Electrocardiographic Patterns, in 24-Hour Holter Monitoring in Patients with Overweight and Obesity.

this study aims to evaluate the prevalence of various arrhythmias and other electrocardiographic patterns within the group of individuals with overweight and obesity. One hundred eighty-one adults (90 females and 91 males) were qualified for inclusion in the experimental group. All participants had a body mass index (BMI) exceeding 25 kg/m2 (98 patients with obesity and 83 with overweight). The mean BMI in the obesity group was 33.6 kg/m2, and all participants had class 1 obesity. The control group comprised 69 individuals (56 females and 13 males) with normal BMI. The basic measurements were performed, and the participants filled out questionnaires describing their health conditions and lifestyles. Each participant underwent an electrocardiographic (ECG) examination and a 24 h Holter ECG examination. In patients with class 1 obesity compared to the control patients, the average numbers of premature ventricular beats (PVBs) and premature supraventricular beats (SPBs) were statistically significantly higher (p = 0.030 and p = 0.042). There was a positive correlation between body weight and PVB (p = 0.028) and between body weight and SPB (p = 0.028). Moreover, BMI and waist circumference were correlated with SPB (p = 0.043 and p = 0.031). In the backward stepwise multivariate regression model considering 24 h Holter ECG monitoring, concerning SPB as the dependent variable, it was observed that BMI (especially obesity class 1), type 2 diabetes, and thyroid disease exhibited the highest regression coefficients. obesity, even in class 1, might be a factor in a more frequent occurrence of abnormalities in electrocardiographic tests.

Catch-AF—Early Diagnosis of Symptomatic Arrythmias in the Waiting Period Prior to Seeing a Cardiologist in Victoria, British Columbia

BackgroundAtrial fibrillation (AF) is the most common cardiac arrhythmia. Given its often-paroxysmal nature, screening at a single time point, using a 12-lead electrocardiogram (ECG) or a Holter monitor, has limited benefit. The AliveCor KardiaMobile device is a validated ECG recorder that can be used for patient-directed arrhythmia diagnosis and symptom–rhythm correlation. The aim of this study was to evaluate whether using the KardiaMobile device could reduce the time-to-diagnosis, for AF as well as other arrhythmias. We hypothesized that providing patients with a KardiaMobile device during their waiting period for specialist care could reduce the length of time that passes before ECG detection of arrhythmia. MethodsPatients were randomized 1:1 to receive either standard monitoring (ECG and a Holter monitor) or enhanced monitoring (ECG, a Holter monitor, and a KardiaMobile device). Patients were instructed to upload ECG recordings if they had cardiac symptoms, so that symptom–rhythm correlation could be achieved. The primary outcome was the time-to-diagnosis for AF. The secondary endpoint was the time-to-diagnosis for any arrhythmias. ResultsFrom October 2018 to October 2022, a total of 69 patients were enrolled, and they were followed up to 12 months. Overall, 6 of the 7 patients diagnosed with AF were in the enhanced-monitoring group (P = 0.106). The time-to-diagnosis was not significantly different in the 2 groups (P = 0.053). Overall arrhythmias were diagnosed in 10 patients (29%) in the standard-monitoring arm, compared to 22 patients (63%) in the enhanced-monitoring arm (P = 0.008). The time-to-diagnosis was reduced in the enhanced-monitoring arm (P = 0.010). ConclusionsThe time-to-diagnosis of any arrhythmia was reduced significantly in patients randomized to receive KardiaMobile device monitoring. Providing patients with a KardiaMobile device may expedite the diagnosis of arrhythmias during the waiting period for specialist care. Clinical Trial RegistrationNCT04302311.

Children and Adolescent Patients with Variants in the ATP1A3 -encoded Sodium-Potassium ATPase Alpha-3 Subunit Demonstrate an Impaired QT Response to Bradycardia and Predisposition to Sinus Node Dysfunction.

Alternating hemiplegia of childhood (AHC) is a rare disorder with both neurologic and cardiac manifestations. The ATP1A3-D801N variant is associated with a pathologically short QT interval and risk of ventricular arrhythmia following bradycardia; however, the mechanism of this remains unknown. We investigated the relationship between heart rate (HR), QT, and QTc, hypothesizing that individuals with ATP1A3-D801N have abnormal, impaired shortening of QT and QTc at lower HR leading to arrhythmia predisposition. We performed a retrospective observational study of individuals who underwent clinical evaluation, Holter monitoring, and genetic testing for AHC at Duke University Hospitals. We also compiled a group of healthy individuals as a control cohort. A larger, worldwide cohort of individuals with ATP1A3 - related phenotypes was compiled to investigate sinus node dysfunction. Linear regression analysis was then performed. The cohort consisted of 44 individuals with ATP1A3 -related phenotypes with 81 Holter recordings (52.27% female; mean age at first Holter 8.04 years, range 0.58 - 33 years), compared to 36 healthy individuals with 57 Holter recordings (52.78% female; mean age at first Holter 9.84 years, range 0.08 - 38 years). Individuals with ATP1A3-D801N had reduced prolongation of QT at lower HR, manifest as a significantly lower slope for HR vs QT compared to healthy (P<0.0001). This resulted in a significantly higher slope of the relationship for HR vs QTc compared to healthy (P<0.0001). Individuals with ATP1A3 - related phenotypes and baseline QTc <350 milliseconds (ms) had increased shortening of QT and QTc at lower HR compared to those with normal QTc (P=0.003; P=0.001). Among worldwide cases, 3 out of 131 individuals with ATP1A3 -related phenotypes required device implantation and/or had sinus pauses >4 seconds. Individuals with the ATP1A3-D801N variant exhibit paradoxical shortening of QT and QTc at lower HR, which contribute to an increased risk of arrhythmias during bradycardia. This is exacerbated by an underlying risk of sinus node dysfunction. What is Known: Individuals with ATP1A3-D801N have a short baseline QTc.Two individuals with AHC experienced ventricular fibrillation following bradycardia. What the Study Adds: The QT and QTc shorten to a greater extent at lower heart rate in individuals with ATP1A3-D801N than in healthy individuals. Individuals with ATP1A3 -related phenotypes and QTc <350ms show greater impairment of QT and QTc dynamics than those with normal QTc. There is low prevalence of device implantation and significant sinus pauses in individuals with ATP1A3 -related phenotypes, with a relatively greater prevalence in those with ATP1A3-D801N.

ИЗМЕНЕНИЯ ЭЛЕКТРОКАРДИОГРАФИЧЕСКИХ ПОКАЗАТЕЛЕЙ ДЕПОЛЯРИЗАЦИИ И РЕПОЛЯРИЗАЦИИ НА ФОНЕ ХИМИОТЕРАПИИ РАКА МОЛОЧНОЙ ЖЕЛЕЗЫ ДОКСОРУБИЦИНОМ

Aim. To study changes in electrocardiographic parameters of the myocardium in patients with verified breast cancer (BC) after completion of chemotherapy (CT) with doxorubicin. Material and methods. The study included 100 patients with a confirmed diagnosis of breast cancer who were treated at the healthcare institution “Grodno University Clinic” (Grodno, Belarus). A number of electrocardiographic parameters of the myocardium were measured in patients before and after chemotherapy using electrocardiography and Holter monitoring. Based on the echocardiography data and the selected threshold value for the relative decrease in GLS (more than 12%), the subjects were divided into two subgroups: those with the presence of cardiotoxicity – CTx+ (n=19) and those without it – CTx- (n=81). Results. An increase in electrocardiographic parameters of depolarization and repolarization (P, P-Q, QRSc, J-Tc, Tpic-Tendc, Q-Tc, Q-Tdc – p&lt;0.001; p&lt;0.001; p=0.005; p=0.023; p=0.009; p&lt;0.001; p=0.006, respectively), as well as in the number of supraventricular extrasystoles (p&lt;0.001) in the general group before and after chemotherapy was detected. The J-Tc and Q-Tc intervals (longer in the CTx- subgroup compared to the CTx+ subgroup: p=0.033 and p=0.037, respectively), the number and total time of sinus tachycardia episodes (p=0.011 and p=0.010, respectively) after chemotherapy differed statistically significantly in the cardiotoxicity subgroups. Conclusions. During chemotherapy with doxorubicin, an increase in the duration of the J-Tc and Q-Tc intervals was observed, the number and duration of episodes of sinus tachycardia also increased. Assessment of the dynamics of these indicators at the stages before/after chemotherapy can provide additional information about the state of the myocardium even before identifying functional disorders by echocardiography.

1893P Incidence of myocardial ischemia during treatment with capecitabine: Assessment with Holter recording and cardiac biomarkers

1893P Incidence of myocardial ischemia during treatment with capecitabine: Assessment with Holter recording and cardiac biomarkers

Coronary Sinus Isolation for High-Burden Atrial Fibrillation: A Randomized Clinical Trial

BackgroundThe coronary sinus is an arrhythmogenic structure that can initiate and maintain atrial fibrillation (AF). Coronary sinus ablation has been shown to be effective in prolonging the AF cycle length and terminating AF in patients with both paroxysmal and persistent AF who have persistent AF after pulmonary vein isolation (PVI). ObjectivesThe objective of this study was to undertake a randomized controlled trial to investigate the efficacy of coronary sinus isolation (CSI) as an adjunctive ablation strategy for the treatment of high-burden AF. MethodsConsecutive patients presenting with symptomatic long episodes of paroxysmal AF (≥48 h but ≤7 days) or persistent AF (>7 days and ≤12 months) referred for first-time ablation were enrolled. Participants were randomized to either PVI, roofline ablation, and CSI (CSI group) or PVI and roofline ablation only (non-CSI group). Participants were assessed postprocedurally via clinical follow-up and 7-day Holter monitoring at regular intervals. The primary outcome was single-procedure drug-free atrial arrhythmia–free survival at 2 years. ResultsOne hundred participants were recruited to the study; 48 were randomized to the CSI group and 52 to the non-CSI group. Acutely successful CSI was achieved in 45 of the 48 patients in the CSI group. At 2 years follow up, 30 of 48 patients (62.5%) in the CSI group and 33 of 52 (63.4%) in the non-CSI group were free from arrhythmia recurrence. Single-procedure drug-free survival at 2 years was no different between groups (P = 0.91). Similarly, multiple procedure drug assisted survival at 5 years was not different between groups (P = 0.80). Complication rates were not significantly different between groups (P = 0.19). ConclusionsAdjunctive CSI as part of a de novo ablation strategy does not confer any additional benefit greater than PVI and roofline for the treatment of high-burden AF.

Revealing the unrevealed: echocardiography for non-ischemic scar tissue detection.

The detection of myocardial scar tissue profoundly influences athletes care and prognostic categorization. Athletes appear to be at risk of developing fatal arrhythmias when harboring a quiescent cardiac disorder. Early identification of disease in asymptomatic individuals through preparticipation screening is means to prevent these events. We presented a male marathon runner master athlete who came at our Department of Sports Medicine for a preparticipation screening. Baseline 12-lead standard electrocardiogram was normal. A maximal cycle ergometer exercise test revealed exercise-induced premature ventricular contractions (PVCs) with uncommon morphology. Echocardiography revealed an hyperechogenic zone at mid-basal posterior segments of the left ventricle. Twenty-four-hours ECG Holter monitoring, with training session, showed some isolated polymorphic PVCs even during training session. Cardiac magnetic resonance (CMR) confirmed the presence of a non-ischemic left ventricular scar (subepicardial) into the mid-basal segment of the posterior wall. Echocardiography is a first-line, economic, and accessible diagnostic test for athletes and it can be useful, when abnormalities are detected, to indicate further investigations, such as CMR. Although non-ischemic left ventricular scarring is difficult to detect on echocardiography, this event is sometimes possible and require further investigation when observed.

A deep learning modular ECG approach for cardiologist assisted adjudication of atrial fibrillation and atrial flutter episodes

BackgroundDetection of atrial tachyarrhythmias (ATA) on long-term ECG recordings is a pre-requisite to reduce ATA-related adverse events. However, the burden of editing massive ECG data is not sustainable. Deep Learning (DL) algorithms provide improved performances on resting ECG databases. However, results on long-term Holter recordings are scarce. ObjectiveWe aimed to build and evaluate a DL modular software using ECG features well known to cardiologists with a user interface that allows cardiologists to adjudicate the results and drive a second DL analysis. MethodsUsing a large (n=187 recordings, 249,419 one-minute samples), beat-to-beat annotated, two-lead Holter database, we built a DL algorithm with a modular structure mimicking expert physician ECG interpretation to classify atrial rhythms. The DL network includes 3 modules (cardiac rhythm regularity, electrical atrial waveform, and raw voltage by time data) followed by a decision network and a long-term weighting factor . The algorithm was validated on an external database. ResultsF1 scores of our classifier were 99% for ATA detection, 95% for Atrial fibrillation and 90% for Atrial flutter respectively. Using the external MIT-database, the classifier obtains F1-score of 97% for the NSR class and 96% for the ATA class. Residual errors could be corrected by manual deactivation of one module in 7/15 of the recordings with an accuracy < 90%. ConclusionA DL modular software using ECG features well known to cardiologists provided an excellent overall performance. Clinically significant residual errors were most often related to the classification of the atrial arrhythmia type (fibrillation vs. flutter). The modular structure of the algorithm helped to edit and correct the AI-based first-pass analysis and will provide a basis for explainability.

Natriuretic Peptide Concentrations and Echocardiography Findings in Patients with Micro-atrial Fibrillation.

Atrial fibrillation (AF) is a rhythm disorder characterized by very rapid and disorganized atrial-derived electrical activations with uncoordinated atrial contractions. Very short periods of AF-like activity (micro-AF) may be precursors of undetected, silent episodes of atrial fibrillation. Here, we examined the relationship between natriuretic peptide concentrations and echocardiography findings in patients with micro-AF. The electrocardiograms (ECGs) of patients complaining of palpitations were recorded with a 24‑hour Holter monitor, and the patients were consecutively included in the study. Micro-AF was defined as sudden, irregular atrial tachycardia lasting less than 30 sec with episodes of ≥5 consecutive supraventricular depolarizations with the absolute absence of p-waves. After a G-power test, patients were consecutively included in the study: 45 patients in the micro-AF group and 45 patients in the control group. Laboratory parameters, ECG and echocardiographic findings of the two groups were compared. N-terminal pro B-type natriuretic peptide (Pro-BNP) and serum troponin T concentrations were higher in the micro-AF group, (375.5±63.6 pg / ml vs. 63.1±56.8 pg / ml, p&lt;0.001; 13±11.4 ng / dl vs. 4.4±2.4 ng / dl, p&lt;0.001 respectively.) Each 1 pg / ml increase in serum Pro-BNP increased the risk of micro-AF by 1.8 %. In the ROC analysis, the cut-off value of Pro-BNP for the diagnosis of micro-AF was 63.4 pg / ml, with a sensitivity of 91.1 % and a specificity of 73.3 %. Atrial electro-mechanical delay durations were significantly higher in the micro-AF group. To predict micro-AF, the inter-annulus plane electromechanical delay time (inter-annulus plane AEMD) had a cut-off value of 18.5 sec, with a sensitivity of 93.3 % and a specificity of 91.1 %. Left intra-annulus plane electro-mechanical delay time (intra-annulus AEMD LEFT) had a cut-off value of 11.5 sec with a 95.6 % sensitivity and 75.6 % specificity. In the ECG evaluation, maximum P wave duration (Pmax) (113±10.2 ms vs. 98±10.4 ms; p&lt;0.001), minimum P wave duration (Pmin) (73.8±5.5 ms vs.70±6.3 ms; p&lt;0.001) and P wave dispersion (PWD) (39.1±7.9 ms vs.28±7.6 ms; p&lt;0.001) were longer in the micro-AF group. Micro-AF in patients may be predicted by evaluating ECG, echocardiographic, and serum natriuretic peptide data.

Radiofrequency catheter ablation of persistent atrial fibrillation by pulmonary vein isolation with or without left atrial posterior wall isolation: long-term outcomes of the CAPLA trial.

Posterior wall isolation (PWI) is commonly incorporated into catheter ablation (CA) strategies for persistent atrial fibrillation (AF) in an attempt to improve outcomes. In the CAPLA randomized study, adjunctive PWI did not improve freedom from atrial arrhythmia at 12 months compared with pulmonary vein isolation (PVI) alone. Whether additional PWI reduces arrhythmia recurrence over the longer term remains unknown. In this multicenter, international, randomized study patients with persistent AF undergoing index CA using radiofrequency (RF) were randomized to PVI+PWI versus PVI alone. Patients underwent regular follow-up including rhythm monitoring for a minimum of 3 years post CA. AF burden at 3 years post-ablation was evaluated with either 28-day continuous ambulatory ECG monitoring, twice daily single-lead ECG or from cardiac implanted device. Evaluated endpoints included freedom from any documented atrial arrhythmia recurrence after a single procedure, AF burden, need for redo catheter ablation, rhythm at last clinical follow-up, healthcare utilisation metrics and AF-related quality of life. 333 of 338 (98.5%) patients (mean age 64.3±9.4 years, 23% female) completed 3-year follow-up, with 169 patients randomized to PVI+PWI and 164 patients to PVI alone. At a median of 3.62 years post-index ablation, freedom from recurrent atrial arrhythmia occurred in 59 patients (35.5%) randomized to PVI+PWI vs 68 patients (42.1%) randomized to PVI alone (HR 1.15, 95% CI 0.88-1.51, p=0.55). Median time to recurrent atrial arrhythmia was 0.53 years (IQR 0.34-1.01 years). Redo ablation was performed in 54 patients (32.0%) in the PVI+PWI group vs 49 patients (29.9%, p=0.68) in the PVI alone group. Pulmonary vein reconnection was present in 54.5% (mean number of reconnected PVs 2.2±0.9) and posterior wall reconnection in 75%. Median AF burden at 3 years was 0% in both groups (IQR 0-0.85% PVI+PWI vs 0-1.43% PVI alone, p=0.49). Sinus rhythm at final clinical follow-up was present in 85.1% with PVI+PWI vs 87.1% with PVI alone (p=0.60). Mean AF Effect On Quality-Of-Life (AFEQT) score at 3 years post-ablation was 88.0±14.8 with PVI+PWI vs 88.9±15.4 with PVI alone (p=0.63). In patients with persistent AF, the addition of PWI to PVI alone at index RF catheter ablation did not significantly improve freedom from atrial arrhythmia recurrence at long-term follow-up. Median AF burden remains low and AF quality of life high at 3 years with either ablation strategy.

Hardware-software implementation of a local Wi-Fi network for the transmission of biomedical signals

The object of this study is a wireless local Wi-Fi network for broadcasting biomedical signals, its structure, and principles of construction. The task of minimizing the power consumption of a Wi-Fi transmitter has been addressed, which provides the possibility of building a wireless system for long-term monitoring of biomedical signals. As a result, a functional diagram of a wireless Holter monitoring system based on an ESP32 microcontroller was constructed, which includes a subsystem for setting up and diagnosing system units using MATLAB software packages, an ECG signal generator, and a multifunctional PCIe board from National Instruments. Evaluation criteria and methods for minimizing power consumption by an autonomous Wi-Fi transmitter have been proposed. Methods for synchronizing the working cycles of the transmitter and receiver of the Holter monitoring system were determined. A procedure for determining the optimal biosignal measurement frequency is presented, at which the distortion of ECG signals would be minimal, which means that the signal could be transmitted without losses. The concept of constructing an algorithm for implementing a program for a Wi-Fi transmitter has been developed, ensuring parallel execution of ECG signal measurement operations and their transmission over a local network. The data from semi-naturalistic tests with an experimental Holter monitoring system with a pre-setup subsystem and using external measuring devices, a computer, and the MATLAB software environment are presented. A comparative analysis of the experimental data with primary ECG signals and ECG signals at the receiver output showed a fairly stable correspondence between the input and output ECG signals. The proposed algorithms make it possible to reduce the average current consumption of the ESP32 microcontroller to 50.5 mA. The results of the study demonstrate the possibility of constructing an energy-efficient wireless system for long-term monitoring of biomedical signals based on the Wi-Fi interface